1. Technical Field of the Invention
The present invention relates to the realization of electrical contacts in microelectronics, for example, during the fabrication of an integrated circuit.
2. Description of Related Art
A contact is defined as the entire volume of a pad serving as the connection point. This pad or contact is often composed of a conductive metal such as TiN, W or Cu.
The electrical contact is established at the interface between the contact pad and a contact zone, for example a silicided semiconducting zone of the active zones of a transistor. The surface of the pad actually in contact with the corresponding contact zone is called the “contact surface.”
In the case of a Metal-Oxide-Semiconductor (MOS), the contact zones can be Source (S), Drain (D) or Gate (G) zones.
In the realization of an integrated circuit, contacts are realized for connecting active devices to the connecting lines. It is known to implement electrical contacts by first depositing a layer of a dielectric material and then using a photolithographic process. The contact placement areas are therefore determined by a masking operation. An anisotropic etching operation is performed to eliminate the dielectric material at the areas not masked by resin in the photolithographic step, so as to expose the areas where the future contacts will be placed.
However, the alignment of the resin mask relative to the underlying levels occurs with a certain overlay, such that the contact placements are also relatively imprecise and therefore imperfectly aligned with the control Gate (G). In the current race towards component miniaturization, alignment limits are becoming more and more restrictive, and there is the fear of short circuits resulting from such imprecision.
There is a need in the art to solve these disadvantages.